The present invention relates to apparatus for sealing the foldable flaps of cartons of random sizes by applying a self-adhesive tape material along the edges of the flaps, and more particularly to an improved plough mechanism for infolding the leading and trailing top flaps prior to the application of the adhesive tape material.
In the packaging industry, corrugated and fiberboard cartons have been used for many years and various machines have been developed which are capable of sealing such cartons either by gluing the flaps, taping the flaps, or by stapling or otherwise providing mechanical fasteners to maintain the flaps in a closed position. Many of these machines are designed to accept cartons of random width and height by providing various types of sensing means to control the transverse movement of the side arms associated therewith and the vertical movement of the top sealing means. Examples of such machines are disclosed in U.S. Pat. No. 4,044,527 and U.S. Pat. No. 4,079,577, both of which have the same assignee as the present invention.
The present invention is directed to an improvement in the mechanism for automatically infolding the top flaps of the carton as disclosed in U.S. Pat. No. 4,079,577. In particular, the invention is directed to an improved plough mechanism which permits the infolding of leading and trailing flaps which are not already leaning towards their infolded position. Prior to the present invention, other devices have been known for infolding the leading and trailing flaps. These devise have included intricate mechanical and pneumatic mechanisms which require critial adjustments for proper operation. Examples of these prior art devices are disclosed in U.S. Pat. Nos. 3,267,640, 3,623,293 and 3,973,375.
Briefly stated, the plough mechanism in accordance with the present invention includes a plough member, a trailing flap folding member, a leading flap folding member, and means for vertically moving the leading and trailing flap folding members between an up position and a down position. The leading flap folding member is pivotally secured to both the plough member and the trailing flap folding member in such a manner that the included angle between the lower flap contacting surfaces of the leading and trailing flap folding members is obtuse when the leading and trailing flap folding members are in their up position and the leading and trailing flap folding members are in substantially the same horizontal plane when the leading and trailing flap folding members are in their down positions. The flap contacting surfaces of the leading and trailing flap folding members are effective to infold the leading and trailing top flaps as the sealing head means is lowered into contact therewith and the leading and trailing flap folding members are moved to their down position. For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings.